[The characteristics of the erythron reaction to dynamic muscle loads in the early postnatal period of rats].

The erythron response to muscular training in 2-6-week old rats involved an increase in concentration of erythrocytes accompanied by no adequate enhancement of the hemoglobin synthesis. Changes of the erythrocyte morphometric indices were revealed. Erythropoiesis increased under the influence of muscular exercises. Quantitative changes of the bone marrow erythroid tissue are the basis of this response. The erythron seems to be able to produce and support only short adaptive erythrocytosis during muscular training in young rats, not the long-term adaptive reactions.